Combination Therapy of Actinomycin D and Cisplatin Achieved Stronger Cytotoxicity via Increasing PUMA Expression on KB Cells

Aim To study the synergistic effect and mechanism of actinomycin D to the anti-cancer activity of cispl- atin on KB cells. Methods Cytotoxicity of actinomycin D on KB cells was evaluated by MTT and LDH Assay. Apoptosis was detected by Flow cytometry （FCM）. Expression of p53, PUMA, Bax, Bcl-2 and Bcl-xl was detected by WB （Western blot） or IF （immunofluorescence staining）. The translocation of PUMA, Bax, Bcl-2 and Bcl-xl was detected by confocal microscope. PUMA knockdown was achieved by PUMA siRNA. Results Actinomycin D synergistically enhanced the cytotoxicity of cisplatin on KB cells. Time-dependent increasing of PUMA and p53 in- duced by actinomycin D was accompanied by the translocation of PUMA and Bax/Bcl-xl in KB cells. Knockdown of PUMA effectively blocked the synergistic effect of actinomycin D to cisplatin. Conclusion Actinomycin D effi- ciently enhanced the anti-cancer activity of cisplatin on KB cells. Up-regulation of PUMA by actinomycin D is like- ly responsible for the observed synergistic effect between the two drugs. Combination of actinomycin D and cisplatin may lead to an effective cancer treatment strategy.